This invention relates generally to fittings to water main systems, and more particularly to a riser conduit which provides variable height positioning of fire hydrants both during and after installation.
The procedure for installing civil fire hydrants in communities has remained essentially the same since the turn of this century. There have been only three noteworthy improvements with respect to the basic installation procedure of fire hydrants during this period, which were the addition of a watch or auxiliary valve, improvements in water thrust restraint as water is directed upwardly into and through the fire hydrant, and the addition of the safety flange break-off feature. Watch valves were introduced to facilitate water supply shut-off directly adjacent the hyrant during routine maintenance, including the height adjustment procedures herebelow described.
In most instances where a commercial water supply system is installed into a residential or commercial development, the final grade level of the area is uncertain. Even in instances where the final grade level is tentatively established, subsequent finalizations of road and curb grade, as well as landscaping alterations, render the initial height positioning of fire hydrants inappropriate. Landscape design often adds or deletes soils around the fire hydrant, thus either unduly exposing or improperly burrying the safety flange. Because it is important to the "breakaway" feature of fire hydrants that the "breakaway" safety joint be fixed at or near grade level, height adjustment of the fire hydrant, responsive to these subsequent alterations of grade, require that the height of the fire hydrant be also altered to re-establish the breakaway joint at or near grade level.
The procedure for inserting extension sections to raise the safety flange of the fire hydrant is so well established that most if not all of the fire hydrant manufacturers currently issue standard written descriptions, including photographs, depicting the procedure for disassembling the fire hydrant at the safety flange and inserting the appropriate extending section (which that company usually manufactures in standard lengths) between the standing pipe and the fire hydrant. These procedures, in conjunction with the standard available lengths of extensions, indirectly describe a further limitation of the present procedure, to wit, the ideal height for the safety flange may not be obtainable because the standard overall lengths of extensions are generally in six inch increments.
The long established and current procedure for adjusting the fire hydrant to the proper grade elevation involves the interruption of water main supply to the fire hydrant and the excavation of the lower barrel or standpipe which interconnects the exposed portion of the fire hydrant and the lower shoe which interconnects to the water main or watch valve. The length of this standpipe, once removed, must be either increased by the addition of extensions, or reduced by installing a shorter length standpipe. Therefore, these subsequent variations in ground level or grade adjacent the fire hydrant are costly and time consuming.
Applicant knows of no less expensive or expeditious method or device currently available on the market which is adapted both to be compatible with the present means for sealing and restraining the fire hydrant against water thrust, as well as providing an economical and expeditious means for varying fire hydrant height responsive to grade variations.
The present invention provides a variable riser conduit which is shaped and adapted to be compatible with presently used mechanical restraint-type joints and also provides for easy and convenient alteration of the vertical positioning of the fire hydrant, either during or subsequent to initial installation, without replacing other components. By excavating the area around the fire hydrant to provide access to this invention, by simply loosening the mechanical joints at either end of this riser conduit, the unit may be rotated with respect to both water main or watch valve and fire hydrant to provide the desired new infinity variable hydrant height positioning within the offset size range of each particular riser conduit. Thereafter, the mechanical restraint joint may be retightened to reattain full sealing and mechanical thrust restraint.